【作者】 赵改名；

【导师】 周光宏；

【作者基本信息】 南京农业大学 ， 食品科学， 2004， 博士

【摘要】 金华火腿是我国传统肉制品的典型代表，也是世界著名的干腌肉制品，但其落后的作坊式加工方法已成为限制其发展的重要因素。目前，金华火腿的传统工艺参数还不具体，而对其加工理论的研究还是很少。本课题是国家863项目“中国传统及特色食品和畜产品生产技术与产品开发”(2002AA248031)中的一部分，目的是在弄清金华火腿传统工艺参数的基础上，研究肌肉蛋白水解酶类的活性变化规律及其影响因素，并结合肌肉蛋白质水解规律和风味物质形成规律，揭示肌肉蛋白水解酶类在金华火腿加工过程中的作用。 从试验设计上，本研究内容主要包括三个方面，一、金华火腿传统工艺参数研究和工艺优化；二、金华火腿传统加工过程中肌肉蛋白质水解变化规律、蛋白酶活力变化规律及挥发性风味物质形成规律的研究；三、肌肉蛋白水解酶的活力影响因素及在金华火腿加工过程中的实际活力变化研究。具体研究內容和结果如下： 1．金华火腿传统工艺优化和主要技术参数间的相关性分析 用JMP软件DOE程序包中Custom Design程序对金华火腿传统工艺进行了6因素3水平优化试验设计，并以144只浙江兰溪当地杂交猪后腿为原料，按照试验设计要求进行了加工试验。以成熟后和后熟后试验火腿的感官评定结果为响应值，用JMP内部分析程序对试验结果进行了方差分析，并用SPSS统计软件对加工过程中的主要技术参数和感官评定结果进行了相关分析。结果表明，腌制期、浸腿时间和成熟期小气候是影响产品质量的重要因素，最佳工艺组合为腌制期30 d，浸腿时间18h，上层挂腿位置小气候成熟条件。腿胚重、用盐量和各主要工序后的产品总失重率之间，及其与产品感官质量指标之间都存在显著相关关系。根据试验结果，用杂交猪后腿加工金华火腿时，腌制后失重率应不低于11％，晒腿后总失重率不低于19％，下楼后总失重率不低于36％。 2．金华火腿加工过程中肌肉蛋白质降解变化的研究 用60只重量在6.2～6.9kg的原料腿按照传统工艺加工金华火腿，分别于24h、31d、51 d、124 d、203 d和264 d各取5只腿的股二头肌样品，分析了肌肉蛋白质的水解指标变化。结果表明，在金华火腿加工过程中，肌肉蛋白质特别是可溶性蛋白质不断发生水解，产生分子质量较小的肽类、游离氨基酸等，加工结束时金华火腿蛋白质的降解指数(P.I.％)在14～20之间。博士学位论文:肌肉蛋白水解酶在传统金华火腿加工过程中作用的研究 肌肉蛋白质水解在不同加工阶段各有其特点.肌肉蛋白质的水解强度以晒腿期间最大，其次是成熟前期和后熟期.掩制期间主要表现为可溶性蛋白质和小于1无Da的肤的水解;成熟前期各种蛋白质和大于1 kDa的肤都发生不同程度的水解，主要产物为小于IkDa的肤;成熟后期主要表现为非蛋白含氮物内部的变化，FAA、分子质量大于10kDa和1一3 kDa的肤比例增大，而其它成分比例下降;后熟期间可溶性蛋白质和大于IkDa的肤都发生不同程度的水解，主要产物为小于1无Da的肤. 在金华火腿加工过程中，除Arg含量变化不大外，其它各种游离氨基酸的浓度随着加工进程而增加。与腌制前相比，火腿中大部分游离氛基酸都提高了10~2O倍，其中切S达80倍以上。加工结束时，火腿股二头肌中含量较高的游离氨基酸主要有Arg、Glu、Leu、琢S、Ala和val等。火腿中大部分游离氛基酸的浓度都超过其感觉闲值多倍，可能对金华火腿的风味产生重要影响。 3.组织蛋白酶B和L在金华火腿加工过程中的活力变化 用上述股二头肌样品测定了肌肉中组织蛋白酶B和L的潜在活力(规定条件下测定的活力)和主要化学成份的变化。结果表明，组织蛋白酶B和L的潜在活力相似，并且在加工过程中都逐渐下降，其中组织蛋白酶B由腌制前1 13犯.05 ug一，下降到后成熟后的1055.32 u.g一‘，加工结束时残余活力为腌制前的9.31%.组织蛋白酶L在晒腿期间有一个不明原因的上升过程，加工结束时残余活力为腌制前的13.66%。在加工过程中，随着环境温度逐渐升高，肌肉中水分含量逐渐下降，肌肉pH值和食盐、脂肪含量逐渐升高，而稍酸钠含量个体差异很大，变化无规律.加工结束时肌肉pH值为5.73左右，含水分50.93%，脂肪8.06%，食盐9.49%，硝酸钠39.35mg·棺一‘。 首次用响应曲面法研究了主要酶活力影响因素对组织蛋白酶B和L活力的影响，并用响应曲面回归方程佑计了组织蛋白酶B和L在金华火腿加工过程中的实际活力(实际加工条件下表现出的活力)变化。研究结果表明，组织蛋白酶B和L的活力受温度、食盐含量和pH值的显著影响(P<0 .001)，并且影响因素之间存在交互作用，而硝酸钠含量在。一50mg’坛一’范围内对组织蛋白酶B和L的活力没有显著影响(P> 0.05).响应曲面回归方程预测结果显示，组织蛋白酶B和L在金华火腿加工过程中的实际活力在大部分时间内都不足其对应潜在活力的5%，但都较为稳定，其总活力(B+L)在腌制之后基本上呈上升趋势，可能对金华火腿加工过程中的蛋白质水解起关健作用。 4.二肤酶I和W在金华火腿加工过程中的活力变化 用上述股二头肌样品测定了肌肉中二肤酶I和IV的潜在活力变化，首次用响应曲面法研究了主要酶活力影响因素对二肤酶I和W的影响，并用响应曲面更多还原

【Abstract】 Jinhua ham is representative of traditional Chinese meat products and is one of the famous dry-cured hams of the world. However, the laggard processing technology primarily adopted in small-scale workshops has become a great hazard limiting its development. In fact, the key parameters used in traditional Jinhua ham processing technology are still not concrete and little work has been done on the research of its processing theory up till now. This research is a part of a National 863 Program item entitled "Producing technology and products exploitation for Chinese traditional & character food and animal products". The aim is to investigate the changes of muscle proteolytic enzyme activities and their influencing factors, after clarifying the processing parameters of the traditional processing technology, study the rules of muscle proteolysis and the formation of flavor substances, and finally elucidates the roles of muscle proteolytic enzymes in the processing of Jinhua ham.By experiment design, the research comprises three parts. The first, study of the processing parameters of traditional Jinhua ham processing technology and its optimization. The second, time-related changes of muscle proteolysis, proteolytic enzyme activities and flavor substances during processing of Jinhua ham. The third, factors influencing muscle proteolytic enzyme activities and changes of the actual activities of the enzymes. The contents and results are as follows. Optimization of traditional Jinhua ham processing technology and correlation analysis on its main technological parametersSix factors and 3 levels optimization experiment design on the traditional processing technology of Jinhua Ham was performed using DOE Custom Design program of JMP software. Experimental Jinhua Hams were processed according to the design with 144 fresh hams from local cross pigs of Lanxi, Zhejiang province, China. Taking sensory evaluation data of the experiment hams after aging and after post-aging as responses, the experiment data were analyzed by JMP variance analysis program, and correlation analysis was also performed on main technological parameters and sensory evaluation data using SPSS. Theresults showed that salting time, soaking time and ham hanging position in aging-loft were the important factors influencing product quality and the optimum technological combination was salting 30d, soaking 18h and aging in a climate similar to that around the upper ham position in the aging-loft. Fresh ham weight, salt dosage, total ham weight loss after each processing stage and product sensory characters were significantly correlated (P<0.05). According to the results, when processing Jinhua ham with green hams from cross pigs, weight losses after salting, sun-drying and loft-aging should not be less than 11%, 19% and 36% respectively. Time-related changes of muscle proteolysis during Jinhua ham processingExperimental Jinhua hams were processed according to traditional processing technology with 60 local cross green hams weighted 6.2 to 6.9 kg. Biceps femoris samples from 5 hams each time were taken on 1 d. 31 d, 51 d, 124 d, 203 d and 264 d and muscle proteolysis indices were analyzed. The results showed that muscle proteins, especially water-soluble proteins were hydrolyzed continuously during processing of Jinhua ham and small molecular products such as peptides and free amino acids (FAA) were generated. At the end of processing, the proteolytic index (P. I. %) of Jinhua ham was 14 to 20.Each processing stage had its characteristic in muscle proteolysis. The most intense proteolysis process happened at sun-drying stage, followed by the first half of loft-aging and post aging stages. Salting stage was characterized by hydrolyzation of water-soluble proteins and peptides smaller than 1 kDa, while almost all proteins and peptides larger than 1 kDa were hydrolyzed to some extent and smaller peptides than 1 kDa generated during the first half of lost-aging period. The second half of loft-aging was characterized by changes of non-protein nitrogen (NPN) components tha更多还原